Active antenna arrays are expected to provide performance improvements and reduce operating costs of communications systems. An active antenna array includes an array of antenna elements. In this context, the antenna element may be viewed as being a transducer which converts between free-space electromagnetic radiation and guided waves. In an active antenna array, each antenna element, or a subgroup of antenna elements, is associated with an active module. The active module may be a low-noise receiver for low-noise amplification of the signal received by its associated antenna element(s), or it may be a power amplifier for amplifying the signal to be transmitted by the associated antenna element(s). The active modules, in addition to providing amplification, ordinarily also provide amplitude and phase control of the signals traversing the module to point the beam(s) of the antenna in the desired direction. In some arrangements, the active module also includes filters, circulators, and/or other functions.
Carefully designed interconnects are needed to transmit a RF signal between two electronic modules or assemblies, such as printed circuit boards. In high-powered RF electronics applications, including RF power amplifiers for cellular base stations, a relatively high amount of energy is transmitted through the interconnect. Signal attenuation may occur as a result of radiation of energy into the air or reflections caused by the signal transfer properties of the interconnect. Therefore, one important characteristic of interconnect assemblies is good signal transfer properties with minimal signal attenuation. Other important characteristics are low cost and ease of manufacture.
Known prior art interconnects are generally mechanical interconnects requiring some form of mechanical coupling to ensure proper RF signal transmission. Conventional methods of constructing interconnects include using blind mate connector systems, metal ribbon connections, and printed circuit pin and spring socket systems. Each of these approaches has shortcomings which include bulkiness in size, the need for manual labor which increases costs, difficulty in manufacturing, and insufficient shielding.
One prior art interconnect that has gained popularity is known as a “Gilbert”™ contact, which consists of a male pin that is soldered or brazed to the next level assembly. The mating contact is a female pin which opens up to allow a male pin to slide into it. Although widely accepted by the industry, it requires a pin to be soldered or brazed at the next level of interconnect, which increases the overall cost of the system.
Another typical example of a prior art interconnect is described in U.S. Pat. No. 4,957,456. The '456 patent describes a self-aligning blind mate RF push-on connector. One problem with the connector described in the '456 patent is its bulkiness, which makes the connector unsuitable for systems with space limitations.
Therefore, a need exists for a RF interconnect that reduces signal attenuation and costs associated with the prior mechanical interconnects. It would therefore represent an advance in the art to provide a RF connector which does not require any special mating provisions except for a pad area.